Post-Modification of Biobased Pyrazines and Their Polyesters

2021 ◽  
Author(s):  
M. A. Würdemann ◽  
T. Faber ◽  
J. A. W. Harings ◽  
K. V. Bernaerts ◽  
R. V. A. Orru ◽  
...  
Keyword(s):  
Post Modification

SuFExable Polymers with Helical Structures Derived from Thionyl Tetrafluoride (SOF4)

2019 ◽  
Author(s):  
Suhua Li ◽  
Gencheng Li ◽  
Bing Gao ◽  
Sidharam P. Pujari ◽  
Xiaoyan Chen ◽  
...  
Keyword(s):  
Functional Polymers ◽  
Polymer Chains ◽  
New Materials ◽  
Helical Structures ◽  
Polymer Backbone ◽  
Silyl Ethers ◽  
Helical Polymer ◽  
Key Characteristics ◽  
Post Modification ◽  
Individual Polymer

The first SuFEx click chemistry synthesis of SOF<sub>4</sub>-derived copolymers based upon the polymerization of bis(iminosulfur oxydifluorides) and bis(aryl silyl ethers) is described. This novel class of SuFEx polymer presents two key characteristics: First, the newly created [-N=S(=O)F-O-] polymer backbone linkages are themselves SuFExable and primed to undergo further high-yielding and precise SuFEx-based post-modification with phenols or amines to yield branched functional polymers. Second, studies of individual polymer chains of several of these new materials indicate the presence of helical polymer structures, which itself suggests a preferential approach of new monomers onto the growing polymer chain upon the formation of the stereogenic linking moiety.

Impact of chemistry on the preparation and post-modification of multilayered hollow microcapsules

2021 ◽  
Author(s):  
Angana Borbora ◽  
Uttam Manna
Keyword(s):  
Chemical Interactions ◽  
Chemical Modifications ◽  
Post Modification

Different chemical interactions/bonding allowed LbL deposition of selected constituents, and further post-chemical modifications of chemically reactive multilayered microcapsules allowed to associate desired chemical functionalities.

Upgrading of Tubular Heat Exchangers by the Helical Spacer Method and Evaluation

2002 ◽  
Author(s):  
F. L. Eisinger ◽  
R. E. Sullivan
Keyword(s):  
Theoretical Analysis ◽  
Acoustic Wave ◽  
Heat Exchangers ◽  
Test Results ◽  
Vibration Testing ◽  
Safe Operation ◽  
Shell Side ◽  
Full Load ◽  
Post Modification ◽  
Side Flow

The tubular heat exchangers described exhibited a sensitivity to flow-induced tube vibration at about 50% of their design shell-side flow. Following a detailed theoretical analysis, the heat exchangers were modified by the helical spacer method providing additional tube supports in-between the existing support plates and in the U-bend. This modification aimed at allowing the heat exchangers to operate safely and reliably at full load, including a 25% overload. Post modification sound and vibration testing was performed which confirmed the adequacy of the modification. The test results showed however, that at the overload condition, an unusual acoustic wave inside the shell was developing. It was determined that this wave would not be harmful to the safe operation of the heat exchangers. The paper will discuss the findings in more detail.

Post-synthetic functionalization and ligand exchange reactions in gold(i) phenylthiolate-based coordination polymers

2020 ◽  
Vol 44 (41) ◽  
pp. 17970-17975
Author(s):  
Larysa Okhrimenko ◽  
Cynthia Cibaka Ndaya ◽  
Alexandra Fateeva ◽  
Gilles Ledoux ◽  
Aude Demessence
Keyword(s):  
Coordination Polymers ◽  
Ligand Exchange ◽  
Exchange Reactions ◽  
Gold Thiolate ◽  
Post Modification

Post-modification and ligand exchange reactions from 1D or 2D gold thiolate coordination polymers occur through a dissolution–recrystallization pathway.

scholarly journals A Versatile Method for Preparing Polysaccharide Conjugates via Thiol-Michael Addition

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1905
Author(s):  
Junyi Chen ◽  
Xutao Ma ◽  
Kevin J. Edgar
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Synthetic Approach ◽  
Renewable Materials ◽  
Fast Reaction ◽  
Michael Additions ◽  
Antimicrobial Performance ◽  
A Charge ◽  
Post Modification ◽  
Fast Reaction Rate

Polysaccharide conjugates are important renewable materials. If properly designed, they may for example be able to carry drugs, be proactive (e.g., with amino acid substituents) and can carry a charge. These aspects can be particularly useful for biomedical applications. Herein, we report a simple approach to preparing polysaccharide conjugates. Thiol-Michael additions can be mild, modular, and efficient, making them useful tools for post-modification and the tailoring of polysaccharide architecture. In this study, hydroxypropyl cellulose (HPC) and dextran (Dex) were modified by methacrylation. The resulting polysaccharide, bearing α,β-unsaturated esters with tunable DS (methacrylate), was reacted with various thiols, including 2-thioethylamine, cysteine, and thiol functional quaternary ammonium salt through thiol-Michael addition, affording functionalized conjugates. This click-like synthetic approach provided several advantages including a fast reaction rate, high conversion, and the use of water as a solvent. Among these polysaccharide conjugates, the ones bearing quaternary ammonium salts exhibited competitive antimicrobial performance, as supported by a minimum inhibitory concentration (MIC) study and tracked by SEM characterization. Overall, this methodology provides a versatile route to polysaccharide conjugates with diverse functionalities, enabling applications such as antimicrobial activity, gene or drug delivery, and biomimicry.

Imidazole-substituted ROMP polymers: Post-modification of poly(norbornenediester) derivatives with aminolysis reactions

2017 ◽  
Vol 111 ◽  
pp. 22-29 ◽  
Author(s):  
Bengi Özgün Öztürk ◽  
Elif Yakut ◽  
Elif Ak ◽  
Solmaz Karabulut Şehitoğlu
Keyword(s):  
Post Modification

Post-Modification of the Interior of Porous Shape-Persistent Organic Cage Compounds

2013 ◽  
Vol 52 (13) ◽  
pp. 3611-3615 ◽  
Author(s):  
Markus W. Schneider ◽  
Iris M. Oppel ◽  
Alexandra Griffin ◽  
Michael Mastalerz
Keyword(s):  
Cage Compounds ◽  
Post Modification

A novel side-chain ferrocene-containing polymer by combination of Cu(0)-mediated SET-LRP of acrylonitrile and post-modification

2018 ◽  
Vol 76 (6) ◽  
pp. 2991-3002
Author(s):  
Liangjiu Bai ◽  
Anyao Ma ◽  
Wenxiang Wang ◽  
Hou Chen ◽  
Zhongxin Xue ◽  
...  
Keyword(s):  
Side Chain ◽  
Post Modification

scholarly journals Fabrication of High-Performance Thin-Film Composite Nanofiltration Membrane by Dynamic Calcium-Carboxyl Intra-Bridging during Post-Treatment

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 137
Author(s):  
Hongyi Han ◽  
Ruobin Dai ◽  
Zhiwei Wang
Keyword(s):  
Thin Film ◽  
Water Purification ◽  
High Performance ◽  
Rejection Rate ◽  
Post Treatment ◽  
Nanofiltration Membrane ◽  
Film Composite ◽  
Thin Film Composite ◽  
Post Modification

Widespread applications of nanofiltration (NF) and reverse osmosis (RO)-based processes for water purification and desalination call for high-performance thin-film composite (TFC) membranes. In this work, a novel and facile modification method was proposed to fabricate high-performance thin-film composite nanofiltration membrane by introducing Ca2+ in the heat post-treatment. The introduction of Ca2+ induced in situ Ca2+-carboxyl intra-bridging, leading to the embedment of Ca2+ in the polyamide (PA) layer. This post modification enhanced the hydrophilicity and surface charge of NF membranes compared to the pristine membrane. More interestingly, the modified membrane had more nodules and exhibited rougher morphology. Such changes brought by the addition of Ca2+ enabled the significant increase of water permeability (increasing from 17.9 L·m−2·h−1·bar−1 to 29.8 L·m−2·h−1·bar−1) while maintaining a high selectivity (Na2SO4 rejection rate of 98.0%). Furthermore, the intra-bridging between calcium and carboxyl imparted the NF membranes with evident antifouling properties, exhibiting milder permeability decline of 4.2% (compared to 16.7% of NF-control) during filtration of sodium alginate solution. The results highlight the potential of using Ca2+-carboxyl intra-bridging post-treatment to fabricate high-performance TFC membranes for water purification and desalination.

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